A new approach to trajectories planner design for a subsonic autonomous aerial fixed wing vehicle

In this study, our aim is to propose an approach to generate the global trajectory an airplane must follow during its mission. In this approach, the problem of piloting an autonomous airplane is treated in two stages: generate and follow the reference trajectory. The first problem is rather an optimization problem with constraints; the second is a problem of control. Toward this aim, we decompose the global trajectory into a set of four elementary trajectories (horizontal level flight, climb, descent and horizontal turn). The second problem to be treated is the interconnection between these elementary trajectories. For this the airplane must follow a non trim trajectory. In this article, we start by defining the two dynamic constraints of equality type related to the under actuation (two differential equations), then we introduce the concept of (permanent) trim trajectories and the (transitional) non trim trajectories. Then, for the first type, we formulate an optimization problem with constraints, minimizing the necessary time for each elementary trajectory; for the transitional trajectories, we solve the equations of underactuation